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REPORTS 


FFICEKS  OF  THE  NAVY 


VEXTELA.TINI-;    AND  COOLI 


SXEGUT1V.E  %i  ENSIGN 


THE  ILLNESS  OF  PRESIDENT  MARFIELD. 


\VA  S .  £1  1  N  (rT 

^w^^^^^^ 

1882, 


REPORTS 


OFFICERS  OF  THE  NAVY 


ON 


VENTILATING  AND  COOLING 


THE 


EXECUTIVE  MANSION 


DURING 


THE  ILLNESS  OF  PRESIDENT  GARFIELD. 


WASHINGTON: 

GOVERNMENT  FEINTING  OFFICE. 

1882. 


3± 


REPORTS 

OF 

OFFICERS    OF   THE 

ON 

VENTILATING  AND  COOLING  THE  EXECUTIVE  MANSION  DURING 
THE  ILLNESS  OF  PRESIDENT  GARFIELD. 


REPORT  OF  PROF.  SIMON  NEWCOMB,  U.  S.  NAVY. 

NAUTICAL  ALMANAC  OFFICE, 

BUREAU  OF  NVAIGATION, 
Washington,  D.  <?.,  February  28,  1882. 

SIR  :  In  compliance  with  your  order  of  the  25th  instant,  I  have  the 
honor  to  present  a  report  of  my  conference  with  the  surgeons  attending 
the  late  President  Garfield  upon  ventilating  the  President's  room  with 
cool  air,  and  of  the  operations  in  which  I  took  part  in  pursuance  of  that 
conference. 

On  the  evening  of  Saturday,  July  9,  Dr.  Woodward,  of  the  attending 
surgeons,  informed  me  that  a  number  of  plans  and  machines  for  cooling 
the  air  of  the  President's  chamber  had  been  proposed  and  several  tried, 
but  that  none  had  proved  effective.  It  was  therefore  desired  by  the  at- 
tending surgeons  that  I  should  examine  all  the  plans,  and  report  in  what 
manner  the  desired  result  might  best  be  reached. 

Among  a  number  of  plans  under  trial,  only  three  demanded  serious 
consideration.  These  were : 

I.  A  large  air  compresser,  such  as  is  used  in  the  Virginia  City  silver 
mines,  which  was  sent  on  by  the  Rand  Manufacturing  Company,  of 
New  York,  and  was  being  mounted  by  engineers  from  the  navy-yard, 
under  direction  of  Mr.  Edward  B.  Dorsey.    This  machine  would  un- 
doubtedly have  been  effective  when  once  in  operation,  but  several  days 
would  be  required  to  get  it  to  work,  and  it  was  doubtful  whether  an 
engine  of  sufficient  power  to  drive  it  could  be  set  up  within  a  reasonable 
time.    As  a  matter  of  fact,  it  was  removed  in  a  few  days  without  being 
tried. 

II.  A  large  ice-box,  which  had  been  placed  in  the  Executive  office, 
and  was  expected  to  cool  the  air  by  a  downward  current  through  the 
ice.     As  the  air  could  pass  through  only  by  descending  under  the  influ- 
ence of  its  own  gravity  it  produced  no  appreciable  cooling  effect,  and 
had  to  be  dismissed  from  farther  consideration. 

III.  A  machine  devised  by  Mr.  R.  S.  Jennings,  of  Baltimore,  consist- 
ing essentially  of  an  iron  box  27  inches  square  by  6£  feet  long,  provided 
with  a  great  number  of  thin  cotton  screens.    These  screens  were  kept  wet 
with  ice- water  percolating  from  a  box  of  melting  ice  on  the  top,  and  the 
air  was  forced  through  the  passages  between  them  by  a  blower.    This 
machine  was  operated  by  a  portable  engine  supplied  from  the  Washington 
navy-yard.    It  was,  however,  necessarily  ineffective  from  the  necessity 

3 

437 


of  melting  the  ice  before  the  latter  could  be  used  in  cooling,  thus  wast- 
ing- the  cooling  power  to  be  obtained  from  the  absorbtion  of  heat  by 
the  melting  ice. 

A  large  body  of  warm  air  passing  between  the  wet  partitions  warmed 
them  and  probably  absorbed  moisture  from  them,  without  itself  becom- 
ing sufficiently  cooled.  I  was  informed  by  Dr.  Woodward  that,  by  clos- 
ing the  doors  and  windows  of  the  Executive  office,  a  slight  cooling  effect 
could  be  observed  with  the  thermometer,  but,  as  all  the  air  admitted  was 
saturated  with  moisture,  the  good  effect  was  neutralized.  Besides,  when 
the  doors  and  windows  were  kept  open,  as  was  necessary  in  the  Presi- 
dent's chamber,  no  cooling  effect  could  be  perceived. 

All  the  proposed  plans  being  either  ineffective  or  impracticable  for 
the  time  being,  it  became  necessary  to  devise  a  new  system.  The  first 
step  necessary  was  to  ascertain,  roughly,  how  many  units  of  heat  per 
day  were  to  be  abstracted  from  the  warm  air,  and  how  much  ice  would 
have  to  be  exposed  and  melted  in  order  to  abstract  this  amount  of  heat. 
One  necessary  datum  in  the  calculation  was  the  quantity  of  cool  air 
required.  This  datum  was  supplied  by  Dr.  Woodward  who  stated  that 
12,000  cubic  feet  of  cool  air  per  hour  was  desirable.  I  then  made  a 
rough  computation  of  the  amount  of  ice  it  was  necessary  that  air  at  the 
temperature  of  95°  should  melt  in  order  that  it  might  be  cooled  off  and 
deposit  the  greater  part  of  its  moisture.  The  principal  parts  of  this 
calculation  were:  1,000  pounds  air  cooled  50°  would  warm  270  pounds 
of  water  50°,  and  would  therefore  melt  about  100  pounds  of  ice  per  hour. 

The  condensation  of  five  grains  of  aqueous  vapor  from  each  cubic 
foot  of  air  would  require  the  condensation  of  some  10  pounds  per  hoar, 
which  would  require  the  melting  of  some  70  pounds  of  ice. 

Therefore,  making  no  allowance  for  waste,  about  170  pounds  of  ice 
per  hour,  or,  say.  two  tons  per  day,  would  have  to  be  melted  by  a  cur- 
rent of  warm  air;  allowing  for  waste,  it  might  be  estimated  that  three 
or  four  tons  of  ice  per  day  must  be  melted  by  the  air  itself. 

The  next  problem  was  to  determine  the  amount  of  ice  surface  which 
must  be  exposed  in  order  to  cool  the  air.  This  was  done  by  taking  a 
block  of  ice  weighing  some  200  pounds,  and  allowing  it  to  stand  over  a 
large  tin  basin  30  minutes.  The  amount  of  water  which  melted  from  it  was 
then  weighed,  and  found  to  be  six  pounds.  Such  a  block  would  therefore 
melt  off  288  pounds  per  day.  To  melt  three  tons  of  ice  it  was  necessary 
that  at  least  three  tons  should  be  kept  in  contact  with  the  cooling  air. 

These  conclusions  were  reached  about  1  o'clock  on  Sunday,  July  10. 
In  reaching  them,  and  putting  them  into  a  practicable  shape^I  co-op- 
erated with  Prof.  J.  W.  Powell,  Director  of  the  Geological  Survey.  He 
and  I  conjointly  devised  a  large  ice  box,  holding  some  six  tons  in  all, 
through  which  the  air  might  pass  in  one  direction  and  return  in  the 
other.  He  took  the  sole  charge  of  its  construction,  and  had  it  ready 
next  morning. 

A  fan  blower  and  transmitting  pipes  for  the  air  being  necessary,  Mr. 
Jennings  kindly  allowed  his  apparatus  to  be  connected  with  the  new 
box,  so  that  the  latter  was  put  into  effective  operation  without  the  ne- 
cessity of  additional  machinery.  The  connection  was  so  made  that  the 
air  passed  first  through  his  box  and  thence  into  the  ice  box.  The  objec- 
tion that  the  air  was  slightly  moistened  and  therefore  injured  in  passing 
through  his  box  was  obviated  by  the  fact  that  the  latter  would  also  act 
as  an  auxiliary  in  cooling  the  air,  while  any  excess  of  moisture  would  be 
absorbed  by  the  ice  in  the  large  box. 

On  Monday,  July  11,  the  air  from  this  apparatus  was  for  the  first 
time  admitted  into  the  President's  chamber  and  found  to  be  cool,  dry, 


ami  amply  in  supply.  A  serious  difficulty  was,  however,  met  with  at 
first  from  the  whirr  of  the  engine  being  distinctly  audible  in  the  Presi- 
dent's chamber,  being  conducted  by  the  tin  tubes  through  which  the  air 
pafiaes.  Mr.  .Jennings  proposed  to  water  jacket  the  tin  pipe,  but  I  sug- 
il  that  an  easier  method  of  cutting  off  the  sound  would  be  to  re- 
move the  tin  tube  and  substitute  one  of  canvas.  This  was  done  and  the 
sound  entirely  ceased. 

Professor  Powell  next  constructed  a  larger  ice-box  in  a  different  part 
of  the  basement  on  plans  of  his  own.  This  new  apparatus  was  also 
supplied  with  an  independent  engine  and  blower  from  the  navy-yard  so 
as  to  be  worked  independently  of  the  other.  Being  primarily  intended 
to  take  the  place  of  the  'first  in  case  of  accident,  it  was  not  connected 
directly  with  the  President's  chamber,  but  with  the  adjacent  corridor. 

From  this  point  Passed  Assistant  Engineer  AVilliam  L.  Bailie,  IT.  S. 
N.,  assisted  by  Passed  Assistant  Engineers  Richard  Inch  and  William 
S.  Moore  took  charge  of  the  operations,  under  orders  of  the  department, 
and  my  active  connection  with  them  terminated.  I  continued,  however, 
to  inspect  the  working  of  the  machinery,  and  held  myself  in  constant 
readiness  to  render  the  engineers  in  charge  any  assistance  which  might 
be  in  my  power. 

The  multiplicity  of  parties  who  took  a  more  or  less  active  part  in  pro- 
posing plans  for  the  object  in  view  being  likely  to  give  rise  to  misap- 
prehension, it  may  be  proper  to  say  that  the  work  of  ventilating  the 
Executive  Mansion  and  the  President's  chamber  with  cool  air  was  in  all 
its  essential  features  designed  and  executed  by  officers  of  the  Navy  and 
Director  Powell,  with  machinery  and  assistance  supplied  by  the  Navy 
Department.  The  most  material  exception  was  that  a  fan  blower  and 
several  feet  of  pipe  for  one  of  the  ice  boxes  was  supplied  by  Mr.  Jennings 
who  assisted  in  putting  the  plans  into  operation. 

It  may  be  added  that  the  mutual  relations  of  the  naval  engineers,  Di- 
rector Powell,  and  myself  were  those  of  friendly  co-operators  towards  the 
end  which  had  been  set' before  us  by  the  President's  surgeons. 
Very  respectfully,  your  obedient  servant, 

SIMON  NEWCOMB, 
Professor,  United  States  Nary. 

Hon.  W.  H.  HUNT, 

Secretary  of  the  Awry,  Navy  Department? 


REPORT  OF  PASSED  ASSISTANT  ENGINEERS  W.  L.  BAILIE,  R.  INCH,  AND 

W.  S.  MOORE,  U.   8.  N. 

WASHINGTON,  D.  C.,  October  31, 1881. 

SIR:  AVe  respectfully  submit  the  following  report  as  the  result  of  our 
observation  of  the  operation  of  the  cooling  apparatus  used  at  the  Exec- 
utive Mansion  during  President  Garfield's  illness: 

There  were  two  systems  of  cooling  apparatus  employed,  one  deliver- 
ing the  cool  air  directly  into  the  President's  room,  and  the  other  deliv- 
ering into  the  corridor  outside  of  the  room. 

Mr.  K.  S.  Jennings,  of  Baltimore,  offered,  and  had  accepted  for  the 
purpose  of  cooling  the  room  occupied  by  the  President,  a  machine  used 
by  him  for  manufacturing  purposes,  and  which  is  represented  in  Plate  A. 

This  machinjB  consisted  of  a  cast-iron  box  2'  3"  by  2'  3"  on  the  end 
and  6'  6"  long,  which  contained  a  number  of  screens  made  of  terry-cot- 
ton, stretched  over  thin  iron  frames,  and  placed  in  the  box  longitudinally 


6 

and  vertically  and  £  of  an  inch  apart;  suspended  inside  and  at  the  top 
of  the  box  was  a  shallow  pan  made  of  galvanized  iron,  which  was  cor- 
rugated and  perforated  at  the  bottom.  On  the  top  of  the  box  was  placed 
a  galvanized  iron  tank  of  about  134  gallons  capacity,  which  was  tilled 
with  granulated  ice  and  salt,  composed  of  64  parts  cracked  ice,  3  parts 
salt,  and  33  parts  water;  this  brine  was  taken  from  the  bottom  of  the 
tank  through  |-inch  pipe  and  delivered  into  the  shallow  pan  in  the  top  of 
fche  box,  through  which  it  percolated,  and  was  distributed  over  the  screens, 
wetting  them  and  reducing  their  temperature  to  that  due  to  the  coin- 
position  of  the  brine.  Attached  to  this  apparatus  was  a  14-inch  Sturte- 
vant  blower,  which  was  used  to.  draw  the  air  into  the  box,  and  between 
the  screens,  reducing  it  to  a  corresponding  temperature,  and  delivering 
it  at  any  desired  point.  This  apparatus  of  Mr.  Jennings  was  connected 
with  the  heating  flue  leading  to  the  President's  chamber,  and  the  air  to 
the  box  was  supplied  from  outside  through  an  air  duct  which  passes 
along  the  top,  and  the  whole  length  of  the  corridor  in  the  basement  of 
the  Executive  Mansion. 

This  cooling  machine  was  soon  found  to  be  of  insufficient  capacity  to 
affect  the  temperature  of  the  President's  room  with  the  windows  open, 
but  with  the  windows  and  doors  closed  it  would  have  reduced  the  air  in 
the  room  to  the  desired  temperature.  As,  however,  it  was  required  that 
the  windows  and  doors  of  the  sick  chamber  be  left  open,  the  problem  of 
how  to  cool  the  room  under  those  conditions  was  presented,  and  the  at- 
tention of  certain  scientific  gentlemen  was  called  to  the  subject.  Mr. 
Jennings  proposed  to  enlarge  the  capacity  of  his  apparatus  by  adding 
two  additional-  boxes,  of  wood,  containing  the  same  system  of  screens, 
to  the  circuit  of  air,  and  by  this  enlargement  he  claimed  the  desired  re- 
sult would  be  effected,  but  in  view  of  the  necessity  of  supplying  the  cool 
air  as  quickly  as  possible,  Prof.  Simon  Newcomb  and  Major  Powell,  of 
the  United  States  Geodetic  Survey,  suggested  the  addition  of  an  ice-box 
to  the  Jennings  machine,  of  sufficient  capacity  to  hold  the  amount  of  ice 
necessary  to  meet  the  emergency,  and  by  a  change  of  pipe  connections 
requiring  the  air  to  pass  first  through  the  Jennings  machine,  and  then 
into  the  ice-box  at  the  top,  and  after  circulating  over  the  ice  to  be  taken 
by  the  blower  and  forced  up  into  the  President's  room.  These  sugges- 
tions were  carried  out,  and  the  effect  was  a  rapid  and  continuous  supply 
of  air  at  about  55°  Fahr.^t  thfc  register  in  the  President's  room,  giving 
the  air  in  the  room  an  agreeable  temperature  during  the  warm  weather 
which  prevailed  at  the  time.  This  apparatus  is  represented  in  Plate  A, 
the  notes  on  the  plate  indicating  its  different  features. 

Subsequently  it  was  ascertained  that  when  a  fresh  breeze  from  the 
south  was  blowing  directly  into  the  President's  room,  through  tne  open 
windows  which  faced  in  that  direction,  it  was  impossible  to  affect  the 
temperature  of  the  room  by  the  small  14-inch  blower  then  in  use.  It  was 
therefore  determined  to  substitute  a  36-inch  blower,  and  reverse  the  cir- 
cuit so  that  the  air  would  pass  first  through  the  ice-box,  then  through 
the  Jennings  machine  to  the  blower,  thence  up  to  the  President's  room. 
By  this  arrangement  the  temperature  was  kept  at  the  desired  point  dur- 
ing the  extremely  hot  weather  which  prevailed  on  August  13  and  14,  which 
may  be  regarded  as  a  good  test  of  the  efficiency  of  the  apparatus. 

By  the  first  arrangement,  represented  in  Plate  A,  it  was  observed  that 
all  the  air  delivered  into  the  President's  room  did  not  pass  through  the 
Jennings  machine,  but  that  a  large  portion  was  drawn  through  the 
leaks  in  the  ice-box;  arrangement  in  Plate  B  obviated  this  difficulty, 
and  assured  the  passage  of  the  air  through  the  pipes  leading  from  the 
air-duct  and  not  from  the  corridor  through  the  leaks,  and  by  extending 


the  induction  pipe  into  the  box  a  better  distribution  of  the  air  over  the 
ice  was  effected. 

The  data  taken  during  the  running  of  this  cooling  apparatus  was  in- 
complete, as  those  who  had  constant  access  to  the  President's  room 
were  too  busily  occupied  to  take  a  systematic  series  of  observations  in 
the  room,  and  it  was  not  until  after  President  Garfield  was  removed  to 
Elberon  that  we  were  able  to  take  the  temperatures  in  the  room  he  occu- 
pied, and  t  his  was  done  September  7  and  8,  during  a  run  of  the  apparatus 
tor  twenty  consecutive  hours,  under  circumstances  as  nearly  as  possible 
like  those  which  existed  during  the  President's  illness  at  the  Executive 
Mansion,  excepting  the  last  hour  of  the  run  when  the  windows  and 
doors  were  closed. 

The  outside  temperature  during  the  special  trial  averaged  84P.9  Fahr., 
and  rimniu'g  the  engine  at  an  average  of  102  revolutions  per  minute, 
and  forcing  22,799  cubic  feet  of  air  into  the  room  per  hour,  resulted 
in  the  reduction  of  the  temperature  of  the  room  5°.4  Fahr.,  and  this 
with  one  window  and  door  open,  and  a  southerly  breeze  blowing. 
Although  this  was  in  a  measure  disappointing,  so  far  as  the  reduction 
of  temperature  was  concerned,  yet  the  character  of  the  air  was  so 
greatly  changed  by  the  reduction  of  the  relative  humidity  of  the  air 
that  if  was  agreeable,  and  could  not  have  been  reduced  to  a  lower  degree 
with  impunity  had  the  patient  been  present. 

We  were  fold  by  one  of  the  President's  attending  physicians  that 
the  first  effect  observed  when  the  cooling  machine  was  started  was  the 
change  in  the  character  of  the  air,  and,  even  before  a  sensible  change  of 
temperature  occurred,  a  benefit  from  the  machine  was  experienced  in 
the  dryness  of  the  air  in  the  room,  which  reduced  the  temperature  of 
the  skin  by  a  more  rapid  evaporation  of  the  moisture  at  its  surface. 
This  effect  is  not  the  least  in  importance;  for,  as  commonly  observed,  a 
warm  day  is  not  necessarily  an  oppressive  day,  if  the  relative  humidity 
of  the  atmosphere  is  not  great.  The  reduction  of  the  relative  humidity 
of  the  air  in  the  President's  room  was  obtained  by  the  operation  of  a 
well-known  law  in  physics,  by  which  the  air  is  deprived  of  a  percentage 
of  its  moisture,  which  it  contains  at  high  temperatures,  when  that  same 
air  is  reduced  to  lower  temperatures. 

The  capacity  for  holding  moisture,  or  vapor,  by  the  atmosphere  is 
greater  at  high  than  at  low  temperatures,  and  is  consequently  deprived 
of  a  part  of  its  moisture  when  passed  over  the  surfaces  of  the  cooling 
machine,  and  this  moisture  the  air  cannot  regain  until  it  escapes  from 
the  system  of  pipes  through  which  it  is  conducted ;  at  the  point  of  its 
escape,  however,  as  its  temperature  rises,  it  claims  that  percentage  of 
moisture  of  which  it  has  been  deprived  in  the  cooling  machine  from  the 
surrounding  atmosphere.  An  examination  of  the  accompanying  Table 
A  will  demonstrate  the  truth  of  this  law.  The  data  were  taken  during 
the  twenty  hours'  trial  after  President  Garfield  was  removed.  The 
relative  humidity  of  the  air  outside  averaged  60,  and  that  of  the  air 
in  the  President's  room  after  passing  through  the  cooling  apparatus 
averaged  54.3.  This  shows  conclusively  that  the  air  of  the  room  gave 
ui>  a  l)ai't  of  its  moisture  to  supply  the  loss  of  moisture  to  the  air  enter- 
ing through  the  cooling  apparatus.  What  the  condition  and  dryness 
would  have  been  had  the  cool  air  been  delivered  into  a  closed  room  we 
have  no  means  of  ascertaining ;  but  from  the  result  of  this  experiment, 
where  the  relative  humidity  of  the  air  in  the  room  was  maintained  at  a 
lower  percentage  than  that  of  the  air  outside,  with  which  it  was  in  com- 
munication through  an  open  window,  it  is  safe  to  assert  that  the  relative 
humidity  of  the  air  in  a  closed  room  can  be  maintained  at  anv  desired 


8 

point.  Charles  Hood,  in  his  book  on  Warming  and  Ventilation,  says: 
«  The  most  healthy  state  of  the  atmosphere  will  be  obtained  when  the 
dew-point  of  the  air  is  not  less  than  10°  nor  more  than  20°  Fabr.  lower 
than  the  temperature  of  the  room.  When  these  limits  are  exceeded  the 
air  will  be  either  too  dry  or  too  damp  for  healthy  respiration."  Exam- 
ination of  Table  A  shows  the  dew-point  to  average  18°.5  lower  than 
the  temperature  at  the  center  of  the  room,  which  proves  by  Hood  to 
have  been  the  most  desirable  condition  of  the  atmosphere  to  maintain. 

In  order  that  the  President's  room  might  by  no  accident  be  deprived 
of  its  supply  of  cold  air,  Major  Powell  devised  a  second  machine,  which 
was  constructed  by  labor  and  material  from  the  navy-yard,  the  differ- 
ence between  it  and  the  other  apparatus  consisting  in  the  arrangement 
of  the  compartments  of  the  ice  box,  as  shown  in  Plate  0,  and  doing 
away  with  the  box  containing  the  terry-cotton  screens.  The  ice-box 
was  divided  into  three  compartments,  an  upper,  middle,  and  lower. 
The  air  was  first  taken  through  the  induction  pipe  and  passed  over  the 
ice  in  the  upper  compartment,  from  thence  down  through  rectangular 
holes  into  the  middle  compartment,  which  it  traversed,  and  was  then 
drawn  into  the  lower  compartment,  and  at  the  opposite  end  the  air  was 
taken  by  a  36-inch  blower  and  forced  through  a  drying-box  up  through 
a  system  of  pipes  to  the  corridor  outside  of  the  President's  chamber. 

The  peculiar  feature  of  this  apparatus  was  the  drying-box,  which  was 
placed  in  the  circuit  for  the  purpose  of  drying  the  air.  This  purpose 
was  supposed  to  be  accomplished  by  cooling  the  bars  of  iron  contained 
in  the  box,  by  causing  a  freezing  mixture  of  ice  and  salt  to  fall  on  the 
ends  of  the  bars,  thereby  cooling  them,  and  by  their  low  temperature 
causing  the  air' to  deposit  on  their  surface  another  portion  of  its  moist- 
ure, after  having  been  deprived  of  a  certain  percentage  in  the  ice-box. 
The  purpose  for  which  the  drying-box  was  intended  was  not  accom- 
plished, as  the  bars  could  not,  by  the  means  employed,  be  reduced  to  a 
lower  temperature  than  the  air  when  it  entered  the  box. 

By  examining  Table  B,  the  data  for  which  were  taken  at  various  times 
as  opportunity  occurred  during  the  time  machine  No.  2  was  employed, 
we  find  that  the  temperatures  taken  just  before  entering  the  drying-box 
average  56°  Fahr.,  and  those  temperatures  taken  just  after  the  air  left 
the  box  average  59°  Fahr.,  or  3°  higher,  showing  that  no  reduction  of 
temperature  was  effected ;  the  relative  humidity  of  the  air  entering  was 
85°.8  and  increased  to  86°.2  on  leaving  the  box,  or  0°.4  greater  on  leaving 
than  when  it  entered,  and  proving  the  box  to  be  of  no  use  MS  a  dryer. 

Comparing  results  at  the  two  ice-boxes,  we  find  the  air  on  leaving 
ice-box  No.  1  to  be  40°.7  Fahr.,  and  leaving  ice-box  No.  2  to  be  53°.5 
Fahr.,  by  which  .we  conclude  that  the  arrangement  of  the  box  into  com- 
partments, did  not  produce  the  best  results,  and  may  be*  accounted  for 
by  the  air  passing  over  the  top  surface  of  the  ice  as  it  lay  packed  upon 
the  floors  of  the  compartments,  and  not  coming  in  contact  with  the  other 
surfaces,  while  in  the  other  box,  which  was  not  divided  but  contained 
shelves  upon  which  the  ice  was  packed,  a  greater  surface  of  the  ice  was 
exposed  to  contact  with  the  circulating  currents  of  air,  which  was  con- 
sequently more  effectually  cooled.  Deflecting  diaphragms  might  have 
been  used  with  advantage  in  box  No.  2,  so  as  to  cause  the  air  to  deflect 
from  the  direct  course  and  come  in  contact  with  the  sides  of  the  ice  as 
well  as  the  top,  and  thus  forcing  the  cold  air  resting  between  the  cakes 
of  ice  into  the  circuit. 

The  effect  of  the  air  delivered  by  this  apparatus  at  the  average  rate 
of  39,217.9  cubic  feet  per  hour,  was  to  keep  the  air  in  the  corridor  at  a 
pleasant  temperature,  although  no  observations  were  taken,  excepting 


at  the  point  the  air  issued  from  the  pipe,  where  the  average  temperature 
was  03.6°  Fahr.  In  the  effort  to  complete  this  apparatus  as  quickly  as 
possible,' right-angle  elbows  were  used  in  all  the  pipe  connections;  the 
effect  was  to  produce  eddying  currents  at  all  the  bends,  the  nature  of 
which  was  noticed  at  the  point  of  delivery  into  the  corridor.  This  elbow 
was  10  inches  in  diameter,  and  the  passage  of  the  air  through  it  pro- 
duced an  eddy  at  the  point  of  delivery,  the  outer  circle  of  which  was  four 
inches  in  diameter,  the  vertical  diameter  extending  one  inch  above,  and 
three,  inches  inside  the  elbow,  the  horizontal  diameter  touching  the  inner 
bend  of  the  elbow.  This  eddy  is  represented  in  plate  0  at  N. 

The  eddy  was  due  to  the^shape  of  the  elbow,  allowing  a  dead  space 
at  M,  into  which  the  emerging  cold  air  falls.  By  reason  of  its  being  of 
greater  specific  gravity  than  the  outer  atmosphere,  it  falls  until  it  is 
again  taken  up  by  the  main  current  of  air  which  causes  it  to  complete 
the  circle.  When  the  elbow  was  replaced  by  a  curved  elbow  the  eddy 
disappeared. 

The  conditions  under  which  the  President's  room  was  cooled  pre- 
cluded all  considerations  of  economy.  The  experiments,  therefore,  are 
without  value  for  the  purpose  of  determining  the  cost  of  ice  sufficient 
to  keep  the  President's  room  at  an  agreeable  temperature  under  more 
favorable  conditions.  The  problem  as  presented  was  the  same  as  to 
ascertain  the  price  of  coal  sufficient  to  keep  the  room  warm  on  a  cold 
day  with  the  windows  open. 

During  the  twenty  hours'  run  8,734  pounds  of  ice  were  melted,  or 
436.7  pounds  per  hour.  This  at  $5  per  ton,  or  one-quarter  of  a  cent  per 
pound,  would  be  $1.09  per  hour;  or  this  was  the  cost  necessary  to  supply 
1*2,799  cubic  feet  of  air  at  50°  Fahr.  at  the  register  per  hour. 

Had  time  been  offered  for  experiment  or  had  experience  suggested  a 
more  economical  method  of  cooling  the  President's  room  much  of  the 
waste  of  cooling  material  might  have  been  avoided,  as  for  instance,  the 
water  of  liquefaction  which  was  allowed  to  run  to  waste  might  have 
been  used  as  a  first  cooling  medium  for  the  air. 

The  experiments  were  also  conducted  under  circumstances  unfavor- 
able for  determining  the  most  accurate  results,  as  the  observations 
would  be  interrupted  at  any  time  the  air  became  too  cool  for  the  com- 
fort of  the  President,  the  experiments,  being,  of  course,  entirely  sec- 
ondary in  consideration ;  yet  a  sufficient  number  of  temperatures  were 
observed  to  show  the  value  of  the  cooling  apparatus,  not  only  as  affect- 
ing the  temperature  of  the  room  occupied  by  the  President,  but  affect- 
ing the  best  hygrometric  condition  of  the  air  in  the  room. 

A  more  general  system  of  experiments  would  be  interesting,  and 
would  furnish  most  valuable  information  as  regards  the  cost  as  well  as- 
the  effects  of  cooling  apparatus. 

Our  operations  at  the  Executive  Mansion  have  brought  to  our  notice 
the  great  importance  of.  a  proper  hygrometric  condition  of  the  atmos- 
phere we  breathe  and  in  which  we  live.  Great  stress  is  laid  upon  the 
subject  by  various  authorities  upon  ventilation  and  warming,  and  not- 
withstanding its  importance  appears  to  be  so  fully  realized,  yet  but 
crude  attempts  have  been  made  to  control  the  hygrometric  condition  of 
the  air  used  in  ventilating  and  warming  our  houses.  In  summer,  with 
the  windows  open,  the  general  condition  of  the  atmosphere  outside  is 
maintained  inside  our  houses,  but  in  winter,  with  windows  closed,  and 
the  ventilation  mostly  dependent  upon  the  warm  air  which  has  passed 
through  the  heaters,  the  conditions  are  entirely  changed.  As,  for  ex- 
ample, the  temperature  of  the  air  outside  we  will  suppose  to  be  20° 
Fahr.;  it  is  passed  through  the  heaters  and  delivered  into  a  room  where 


10 

the  temperature  is  maintained  at  70°  Fahr. ;  supposing  the  windows  to 
be  closed  and  only  leakage  sufficient  to  permit  ventilation,  we  will  have 
in  this  room  air  at  the  temperature  of  70°,  the  dew-point  of  which  is  not 
above  20° ;  for  in  the  manner  our  heaters  are  usually  constructed  there 
are  no  means  by  which  the  air  can  receive  moisture  after  it  has  left  the 
outside  of  the  house. 

The  most  healthful  condition  of  the  air  is  found  to  exist  when  its  rela- 
tive humidity  is  from  50  to  70  per  cent.  In  the  hypothetical  case  cited, 
the  relative  humidity  is  as  low  as  15  per  cent.,  an  extreme  that  must  be 
not  only  unpleasant  but  injurious.  Of  course  crude  attempts  have  been 
made  to  remedy  this  evil  by  urns  of  water  placed  over  or  near  the  heat- 
ers, but  in  most  instances  even  this  is  wanting.  It  being  necessary  that 
the  dew-point  should  not  be  less  than  20°  below  the  temperature  of 
the  room,  it  may  be  increased  as  it  enters  from  the  outside  by  passing 
it  through  water  at  a  given  temperature,  say  55°  before  entering  the 
furnace,  saturating  the  air  and  establishing  the  dew-point  at  that  tem- 
perature, the  relative  humidity  being  58. 

Our  operations  at  the  Executive  Mansion  have  proved  that  it  is  pos- 
sible to  place  the  dew-points,  or  relative  humidity  of  definite  quantities  of 
air,  at  any  desired  point,  and  there  is  no  reason  why  this  hygrometric 
condition  may  not  be  maintained  with  as  much  certainty  as  the  amount 
and  temperature  of  air  supplied  for  proper  ventilation  and  warming. 
This  field  of  study  presents  great  opportunities  for  effecting  a  better 
condition  of  the  atmosphere  of  our  rooms,  and  our  personal  comfort  and 
health  may  be  improved  in  proportion  to  our  careful  observation  of  the 
hygrometric  condition  of  air  in  which  we  live.  Hospitals  and  public 
buildings  ought  to  be  especially  protected  from  the  evil  results  attend- 
ing a  vitiated  condition  of  the  air,  and  we  can  see  no  reason  why  their 
atmosphere  may  not  be  made  comfortable  and  healthful  at  all  seasons 
and  under  all  conditions  of  the  outside  air. 

Hoping  the  few  results  obtained  from  our  experiments  may  be  useful 
in  calling  more  general  attention  to  this  subject,  and  expressing  our 
thanks  to  the  United  States  Signal  Officer  for  valuable  information  and 
the  use  of  instruments, 

We  are,  very  respectfully,  your  obedient  servants, 

WM.  L.  BAILIE, 
Passed  Assistant  Engineer,  U.  S.  N. 

BIOHAED  INCH, 
Passed  Assistant  Engineer,  U.  S.  N. 

W.  S.  MOOEE, 

Passed  Assistant  Engineer,  U+S.  y. 
Engineer  in  Chief  W.  H.  SHOCK,  U.  S.  N., 

Chief  Bureau  of  Steam  Engineering, 

Navy  Department,  Washington,  D.  C. 


11 

TABLE  A. 


Datr  and 
hour. 


S.-pr.  7. 
188L 

4  p.  m 

5  p.  m 

6  p.  m  . . 

7  p.  m 

8  p.  m 

9  p.  m 

10  p.  m 

11  p.  m  . . 

12  mid... 
1  a.  m  . . 
•J  a.  in  . . 
:;  a.  m  . . 

4  a.  m  . . 

5  a.  m  .. 

6  a.  m 

7  a.  m  . . 

8  a.  m  . . 

9  a.  m  . . 

10  a.  m.  .. 

11  a.  m*. 


30.  040  98 
30.  030  97 
30.  020  92. 


30.  050  87. 
30.  062  87. 
30.  080  84 
30.  090  84 
30.  069  83 
30.  060  81. 
30.  064  80 


Outside. 

A. 

B. 

C. 

D. 

«J 

£ 

| 

f 

4 

i 

^ 

>» 

-ri 

.2 

= 

.3 

'g 

« 

"g 

=. 

'2 

~ 

b 

- 

i 

a 

5 

1 

1 

I 

A 
I 

I 

4 

S, 

1 

S3 

A 

i 

i 

1 

1 

1 

A 
1 

£ 

P 

1 

3 

98 

76 

64 

34 

83.5 

71.:. 

64 

53 

38 

38 

38 

100 

47.5 

42 

34 

61 

52 

62 

97 

76     65 

35   84     72     65 

53     '39     38 

36 

89 

43 

43 

43 

100 

50 

58 

92.5 

76     68 

46   85     73     66 

53     |40     39     37     89 

42 

42 

42 

100  149* 

57 

89 

76     69 

52   86     74     68     55     i39     38.537     92 

42     42     i42 

100   49 

87.5 

77     72       61    86     |76     71     61      39 

38     36     89 

41.541     41 

95   49  • 

56 

87.  5  77.  5  72 

72   86.  5!73     66     51     39 

38.  5  37     92     J42 

41     40 

92   48.  5  55 

84.  5  76     72 

67   86.573     66     51     39 

38.  5  37     92     41 

41     41 

100   48.555 

84 

7G     72       67    87     ,75     69     55     39     38.537     92     41     41     41 

100   48.  5  54 

30.  080  78 
30.  085  77 
30. 100  77 
30. 115  78 
30. 125  81 
30. 135  84 
30. 130  90 
30. 134  90 


74  69 
5  74     70 

71.566 
572     |68 

j71  167 
71  68 
70  !66 
70.  5  65 
7'J  (i7 
73.  5  67 
7:.  r,7 

75  67 


Averagest 84.  6  73. 


70   87.  5  T:. 

62   86     J73.566 

69   86. 57:i 


141  41  41 

42  42  42 

42  42  42 

42  42  !42 


47 
4S 


48    154 


41.  5  41.  5  41.  5 100  |47.  5  54 
41.  5  41.  5  41.  5  100 
|41    (41     41      100 

100 

LOO 

,42  J42  42  100 
42  41.541.5  95 
'43  42  J41  |  92 
;43  J43  41!  100 
•43.  5  43.  5  43.  5 100 


4S 
48 
48 
49 


,50 
43     43     ;43     ilOO   51 


60   85     73.366.251.940.539 


37.  3  90.  7  42.  3  41.  8  41.  3  96.  5  48.  8  55. 1 
I        I        I        I        I        I        I    .     I 


l);it<-  and  hour. 


Temperatures. 


Center  of  room. 


g      ii 


! 


Box  of  the  Jen- 
niiigs  machine. 


P 

£   P   « 

P   P 

o 

t 

> 

fi 

4 

Sept.  7,  1881. 
4  p.  m  89. 
5  p.  m  82 

r.  7J   til   39 
72  6fi  :.u 
70  62  48 
70  62  48 
68  60  49 
70  63  54 
67  58  47 
67.  5  59  51 
66  58  51 
67  60  54 
67  60  54 
'67  60  54 
J68  62  58 
5  68.  5  62  58 
569  64  63 
68  62  58 
5  68.  5  62  64 
5:68  62  60 
567  60  64 
63  55  51 

' 

300 
75 
95 
240 
0 
0 
0 
0 
9 
-  96 
—  95 
—  96 
—  73 
0 
—105 
—130 
—165 
—100 
—  66 

100 
100 
100 
100 
103 
100 
100 
107 
108 
105 
108 
102 
99 
102 
102 
102 
102 
102 
102 
102 

4807520 
4900360 
5013218 
5122266 
5217960 
5316300 
5406438 
5517798 
5623552 

790 

20 

120 

7pm          83 

8  p.  m  81 

9pm         81 

59 
57 
56 
56.5 
57 
56 
56 

56 
56 
57 
56 

53.  5'47 
51   4.". 
52  48 
52  48 
52  47 
51  46 
51  46 
51  46 
51  46 
51  46 
51  45 
51  46 

65 
64 
74 
74 
69 
69 
69 
69 
69 
69 
64 
69 

10  p  m         80 

11  p  m         79 

Y2  midnight      78 

1  a.  m  78 

372 

14 

100 

•J  a.  in           78 

5822144 

3  a.  in  78 

4  a.  m          78 

6019572 

5  a.  m  78 

6226380 
6325740 
6417348 
6510690 
6601538 
6701340 

7  a  .  1  1  1  ......      78 

200 

14 

80 

8  a  m           77 

9a.m  77. 
10  a  m          77 

57 

58 

52 
52 

47 
46 

69 
64 

11  a.  m*  74 

Averagest  ....  79.  7  68.  4  61.  2  54.  3  56.  5  51.  5  46.  3  68.  3 

*  Window  and  door  closed. 


t  For  the  19  hours  with  window  and  door  open. 


12 

TABLE  B. 


Date  and  hour. 

Barometer  corrected  for 
temperature,  e  1  ev  a- 
tion,  and  instrument 
error. 

Temperatures. 

Outside. 

Induction  pie  of  blower. 

t>S 

g 

t 

Dew  point. 

I 
I 

£ 

n 

1 

Dew  point. 

a 

a 

^ 

1 

29.  791 

.746 
.725 
.802 
.789 
.780 
.741 
.736 
.824 
.779 
.895 
.867 
.913 
.873 
.907 
30.  122 

.on 

29.  934 
.923 
.863 
.876 
/     .760 
.736 
.755 
.710 

83 
84 
81 
78 
75 
77 
83 
81 
73 
78 
87 
83 
84 
87 
78 
86 
90 
95 
80 
83 
87 
90 
91 
90 
96 

73 
71 

70 
72 
71 
72 
75 
74 
68 
76 
75 
72 
72 
73 
69 
75.5 
76.5 
76 
74    - 
73 
76 
75 
75 
76 
78 

68 
63 
67 
69 
69 
69 
71 
70 
65 
75 
69 
66 
65 
65 
64 
69 
69 
66 
71 
68 
70 
67 
66 
69 
69 

61 

49 
62 
74 
82 
76 
67 
69 
76 
91 
55 
57 
53 
48 
62 
57 
50 
40 
74 
61 
57 
47 
.    44 
50 
41 

53 

47 
47 
50 
50 
60 
58 
46 
47 

11 

45 
52 
48.5 
54 
51.3 
73.5 
65 
55 
56 
56 
49 
48 
64 
67 

53 
46 
46 
48 
49 
57 
58 

9 

£ 

44 
50 

47 
52 
51 
70.5 
62 
54 
55.  5 
55 
48 
47.5 
6.'{ 
66 

53 

45 
45 
46 
48 
54 
58 

8 

11 

43 
48 

3 

11 

60 
53 
56 
54 
47 
48 
62 
65 

100 
93 
93 
86 
93 
81 
100 
93 
100 
93 
100 
93 
86 
93 
86 
100 
84 
84 
93 
97 
93 
93 
97 
93 
93 

July  17*  3p  m           -  -  • 

July  21  11am                 

July#Jl'  7pm                     

July  22'  7  a.  m      ...•.  -.  

July  22  11  a  m 

July  26  11  am               

July  26  3p  m    

July  27  11  a  m                . 

August  4  11  am            

August  63pm                    

August  9  3  p.  m  '  

August  10  1*2  m 

August  10  3  p.  m                     

August  13,  11  a.  m  

August  13'  3pm 

Averages 

84 

73.5 

68 

59.  7J     53.5 

-9    o 

50 

90 

Date  and  hour. 

Temperatures. 

At  box  before  entering. 

At  box  after  leaving. 

Corridor. 

a 

3 

.3 
1 

jj> 

Q 

-^ 
e 

-R 

A 

§, 

1 

a 

3 
A  . 

1 

j? 

56.5 
53 
53 
51.5 
54 
60 
62 
52 
51 
52 
55 
52 
55 
56 
57  • 
56.5 
73 
73 
64 
64 
63 
62 
60 
68 
70 

i 

* 

•1 

'I 

•1 

I 

2 

'     -« 

a 

1 
t    J    1     ,     J 

July  17,  lla.m  
July  17  3  p.  m 

56 
53 
53 
51 
53 
'  58 
61 
47 
49 
49 
53 
48 
53 
51 
55 
54 
75 
69 
58 
59 
50 
53 
52 
66 
68 

54 
48 
48 
49 
49 
56 
60 
45 
48 
48 
51 
46 
51 
48 
53.5 
53 
71 
66 
56 
57.5 
57 
51 
51 
65 
66 

52 
42 
42 
47 
44 
54 
59 
43 
47 
47 
49 
44 
49 
45 
52 
52 
69 
64 
54 
58 
55 
49 
50 
64 
65 

86 
66 
66 
86 
72 
87 
93 
86 
97 
97 
86 
86 
86 
80 
90 
93 
82 
84 
87 
96 
87 
86 
93 
94 
90 

55 
52 
51 
51 
53 
57 
61 
51 
50 
50 
53 
50 
52.5 
51 
54 
54 
71 
71 
61 
61.5 
59 
59 
57 
66 
67 

55.5 
51 
49 
51 
52 
54 
60 
50 
49 
48 
51 
48 
50 
46 
51 
53 
70 
70 
59 
59 
56 
57 
54 
65 
65 

96 
93 
86 
96 
93 
81 
93 
93 
93 
86 
86 
86 
83 
69 
80 
90 
90 
90 
85 
85 
78 
84 
81 
90 
84 

61.5 
59 
54 
58 
59 
62 
67 
61 
61 
57 
63 
61 
59.5 
60 
62. 
64 
75 
73 
66 
68 
67 
66 
64 
70 
72 

60.5 
54 
52 
56 
58 
60 
65 
57 
58.5 
54 
60 
59  , 
55.5 
53.5 
58 
57.5 
72 
68 
62 
64 
62 
61 
60 
67 
67 

61 
49 
50 

@ 

58 
64 
54 
56 
51 
58 
57 
51 
46 
55 
52 
70 
65 
59 
61 
58 
57 
57 
65 
64 

97 
70 
86 
86 
93 
87 
90 
78 
84 
81 
84 
87 
75 
60 
78 
75 
85 
76 
78 
78 
73 
73 
78 
84 
76 

July  20  11  p  m 

July  21,  7  a.  m  

July  21,  11  a.m  
Jul>  21,  3  p.  m  

July  21  7  p.  m 

July  22,  7  a.  m  

July  22  11  a.  m 

July  25,  3  p.  m  

July  25  7  p.  m 

July  26,  11  a.m  

July  26>  3  p.  m 

July  27,  11  a.m  

August  4,  11  a  m 

August  6,  11  a.m  
August  6,  3p.m  
August  7,  11  a.  m  

August  7,  3  p.  m 

August  9,  3  p.  m  

August  10,  12  m  .  . 

August  10,  3  p.  m  

August  13,  11  a.  m. 

August  13,  3  p.  m  

Averages    .  . 

56.1 

53.9 

51.  8,     85.  5     58.  9 

56.  7     54.  9 

85.  8!     63.  6     60 

57.1 

80 

13 

TABLE  B — Continued. 


Date  and  hour. 

Air-meter. 

Revolutions  perminute. 

i 

Remarks. 

\ 
Lineal  feet. 

Rate  per  hour  cor- 
rected for  error 
of  instrument. 

July  17  11  a.  in                      

3,  932,  748 
4,  212,  799 
4,  494,  530 
4,  758,  650 
5,  275,  230 
5,  594,  040 
5,  883,  420 
6,  196,  250 
6,  714,  720 
6,  949,  060 
7  431  440 

69,  953 
62,284 
63,270 

98.6 
95.3 
96.5 
87.2 
72.1 
109.7 
98 
70.5 
70 
82.3 
74.5 
70 
79 
102 
94 
49.9 
108 
156.1 
147 
143.2 
97.5 
131.1 
97 
92.3 
103.3 

40 
40 
40 
40 
40 
40 
40 
40 
40 
40 
40 
40 
40  . 
40 
40 
30 
40 
40 
40 
40 
35 
40 
40 
40 
40 

Ice  in  drying  box. 
Do. 
Do. 
Do. 
Do. 
No  ice  in  drying  box. 
Do. 
Ice  in  drying  box. 
No  ice  in  drying  box. 
Ice  in  drying  box. 
Do. 
Do. 
No  ice  in  drying  box. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 

July  °l'  7  a.  m 

49,  852 
57,  717 
68,253 
74,297 
47,  418 
55,556 

July  21*  11  a  m 

July  21  3  p.  m       ..     .  .......  

July  21  7  p  m 

July22'7a.m                        

July  22'  11  a.  m  

July  25'  3pm 

7,  614,  730 
8,  531,  330 
8,  837,  830 
10,  260,  440 
12,  014,  130 
'13,870,750 
14,  324,  130 
16,  340,  500 
16,  753,  600 
17,  545,  820 
18,  134,  200 
18,  465,  300 
21,  168,  970 
21,  456,  800 

43,  031 
55,547 
72,784 
64,135 
33,  701 
74,  340 
107,  683 
93,  777 
98,  112 

July  26  11  a.  m 

July  26  3pm          .       ... 

July  27  11  a.  m  

August  4  11  a.  111                      .... 

August  6  11  a.  m     

August  7  Ha.  111    ...     .     ....  .....   .. 

August  9,'  3  p.  m  
August  10,  12  m       

August  10  3  p  m 

87,  015 
64,  830 
68,  360 

August  13,  11  a.  111         .  . 

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